Solar panel element

ABSTRACT

The purpose of this invention is to indicate a solar panel element, wherein the solar panel element may constitute an integrated and aesthetically attractive covering element for covering a building envelope, where the solar panel element can be mounted without changing possibly existing underlying structures and follow the architecture in the surrounding covering of the building. Moreover, it is aimed at mounting a solar panel element which is completely or partially produced under quality-assuring conditions. This purpose is achieved by a solar panel element consisting of a transmission plate, an absorber housing and an absorber member. 
     The solar panel element according to the invention is peculiar in that the transmission plate has greater extension than the absorber housing, and that the transmission plate, compared with the absorber housing, has a protruding part, preferably for overlapping on a roof or façade element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns a solar panel element for thermal utilisation of solar radiation, the solar panel element constituting a roof or facade element for covering a building, the solar panel element including a transmission sheet or plate, an absorber member and an absorber housing, where the transmission plate is adapted for passage of solar radiation, where the absorber member includes means for transforming solar radiation to heat radiation/heat conduction and for transmitting the heat radiation/heat conduction to at least one tube which is connected with the absorber member, and which is intended for containing a heat absorbing liquid medium, where the absorber housing includes connecting means for the transmission sheet or plate, where the solar panel element is provided with projecting means along one or more edges, where these means form direct or indirect transition to the surrounding covering and at the same time are an extension of the transmission plate.

2. Description of Related Art

It is well-known to use solar panel elements which are typically mounted on the part of a house roof which is sunlit the most during the day. The solar panel elements are most often an independent element which is mounted over the other roof covering. Sometimes, the solar panel element is countersunk into the surrounding roof covering with flashing methods corresponding to flashing a roof window.

Finally, in recent years initiatives have been taken to provide solar panels as a more integrated part of building architecture.

Inter alia as described in US 2005/0016524, where a number of absorber panels consisting of an absorber housing and an absorber member are disposed between the laths under a roofing of translucent tiles in the form of glass sheets covering the roof corresponding to slate tiles. The drawback of this method is that mounting the absorber and the translucent tiles has to be done very carefully and in times without precipitation as the efficiency and appearance of the solar panel will depend on that dirt, dust and fatty marks do no appear on particularly the inner side of the translucent tiles. Moreover, the efficiency depends on a sealing between the individual absorber panels in order to avoid that the heat by convection moves up into the upper part of the solar panel, thereby lowering the total efficiency of the absorber panels. This sealing may only be poorly ensured by this solution, why there must be counted with a relatively large heat loss due to convection in this type of solar panel. In order to ensure sufficient service life and correct making of the sealing, this work is thus to be done very carefully under mounting conditions without precipitation and with a sealing mass which is resistant to sunlight and large temperature fluctuations. Therefore, there is a need for a well-trained skilled person and the right weather in order to perform in the work with mounting a solar panel unit of this type.

In FR 2 427 558 another known solution is mentioned. Also this solution has drawbacks related to the object of the invention as several absorber panels have to be used to cover a certain area of a roof. Thus the overall efficiency will be lover and the work during installation will be more time consuming as the individual absorber panels will have to be connected by some kind of plumbing. A further drawback in this solution is that there is a potential risk of a leakage in every joint in the pluming and the number of the joints will at least be the same amount as the number of absorber panels. If this solution should be installed covering a larger area there will be a need for installation of several absorber panels with the above mentioned drawbacks.

The document WO 2007/099291 mentions a solar panel element where the solar panel element can be mounted as a finished unit corresponding to a weather boarding where there is sealing in the joint with a corresponding solar panel element at the side, and where the solar panel element lies with an overlap over the below situated solar panel element.

The disadvantage is that the solar panel element disclosed by the document differ aesthetically from the well-known roofing and façade coverings as the solar panel element at its overlapping edge is composed by a glass and a support flange from the absorber housing. This provides a relatively large difference in height between the two solar panel elements in the overlap. At the same time, two types of materials will appear in the surface of the roof which will patinate differently under the action of sun, wind and weather as coloured surfaces may fade over time.

Moreover, the absorber housing is resource demanding to make, as it is either a moulded unit or an extruded item which afterwards is machined by milling for draining, ventilating and points of fastening.

Furthermore, a certain design of the substructure is required since the lath spacing is decisive for correct implementation. The described solar panel element is thus not well suited for incorporating in existing building covering.

SUMMARY OF THE INVENTION

The purpose of this invention is to indicate a solar panel element, wherein the solar panel element constitutes an integrated and aesthetically attractive covering element for covering a building envelope, where the solar panel element preferably can be mounted without changing possibly existing underlying structures and follow the architecture in the surrounding covering of the building.

Moreover, it is desired to possibly mounting a solar panel element which is completely or partially finished under quality-assuring conditions, and where the efficiency of the solar panel element is optimised by reducing the possibility of heat loss due to convection in the solar panel element.

DESCRIPTION OF THE INVENTION

According to the present invention, this object is achieved by a solar panel element of the type indicated in the introduction, which is peculiar in that the solar panel element is provided with projecting means along one or more edges, where these means form direct or indirect transition to the surrounding covering and at the same time are an extension of the transmission plate.

A preferred embodiment of the invention is a solar panel element with a size corresponding to at least several of the other roofing elements, e.g. a solar panel element with a size corresponding to several vertical as well as horizontal roofing elements. This solar panel element is provided with means for individual adjustment of the spacing between respective vertical and/or horizontal rows of transmission elements. In other words, it is possible to adjust a solar panel element according to the invention to precisely the lath spacing applied in the construction in question, whereby the finished appearance with a solar panel of appreciable size will not deviate from the general appearance, as the diagonal, the vertical and the horizontal lines are retained.

Such a solar panel element may e.g. be with a height corresponding to three horizontal rows of roofing elements and with a width corresponding to ten vertical rows of roofing elements. By arranging horizontal and possibly vertical beams under the transmission plate which either rests on the absorber housing or the absorber member, or alternatively is self-supporting, there may be performed individual adjustment of parts of the transmission plate such that the lines of the roof face are followed. The adjustment itself may occur with adapted spacers which are exchanged or selected according to need. Of course, there are different ways of performing this adjustment, and it is within the capability of a skilled in the art to perform such a task. A typical adjustment spacing is between 0 and 50 mm, but even greater adjustment spacings may find application.

Hereby may be achieved that the solar panel element may constitute a roof or facade covering tile which can be made under quality assured conditions in a factory or similar. The transmission element, the absorber member and the absorber housing are assembled during the production process with great certainty of uniform quality, including ensuring purity of the glass. This reduces the time of mounting when fitting the solar panel element, the requirements for training the fitter and prevents possible errors and deterioration during mounting. By absorber housing is meant the part of the solar panel element disposed under and/or along the sides of a transmission element and which contributes to securing the absorber member. The absorber housing can be made of all types of materials, e.g. metal, plastic, composites, and may e.g. be provided by moulding the desired material, or by bending/extrusion/pultrusion with added end closure. The absorber housing most often has a cavity in which the absorber member may be placed, with an insulating step below.

The means of the absorber housing for securing the absorber member may be constituted by recessed longitudinal grooves, projecting support pins or projecting longitudinal flanges at opposing inner walls of the absorber housing.

The transmission plate is translucent for sunlight and is typically made of glass, but it may also be of plastic or composite which is not opaque but more or less translucent. Some types of glass are provided with an embossing in the surface, making the glass less reflective to sunlight such that the radiation is increased compared with flat glass.

Since the transmission plate of the solar panel element may have a thickness corresponding to a common covering tile, the solar panel elements may readily be added to an existing covering without entailing either increased offset in the element overlapping or greater installation height, and thereby change of the optical dimensions of the covering surface. The surface of the solar panel element serves as covering surface just as the existing covering. For example, this means that covering of roofs and facades of natural slate or fibre-cement slate may be added an efficient solar panel element without substantially changing the architectural expression.

If the entire surface of a building part is covered by the solar panel element there is achieved an aesthetically attractive result corresponding to known forms of weather boarding with e.g. slate tiles. Here it is possible to let part of the covering elements be without absorber member such that the optical impression of the surface of the construction appears completely uniform.

That the surface of the solar panel element facing the outer side of the construction is made of the same material also results in uniform patinating. For example, there are no visible coloured surfaces that may fade and change their colour over time.

The solar panel element according to the invention may be integrated in most of existing roof systems, including standard constructions with wooden laths, where additionally there is provided for unchanged roofing underlay solutions and adapted lathing. Thereby it is relatively simple to remove existing roof and facade covering and to immediately mount a roof or a facade consisting of solar panel elements. The surface of the roof or façade covering will typically be with an inclination between 20° and 90° relative to horizontal.

By providing the solar panel element with the projecting means, it is possible integrate the solar panel element completely in e.g. a roof surface. This is possible as the projecting means may either be arranged over or under the adjacent covering elements and thereby ensure that the optical appearance of e.g. a roof surface is not disturbed. By the invention it is thus possible to use a solar panel element with a given size in a roof surface without it being clearly visible. This is achieved inter alia by providing the solar panel element with a corresponding or similar corrugation as the roof covering. The projecting means may advantageously be designed such that they can be adapted or so that they are already adapted to the surrounding covering elements.

The projecting means are in principle a kind of adapter profile which is fitted on the transmission element and/or the absorber housing, and may have a design corresponding to the part of the surrounding roofing elements that are adapted for disposition under the overlap from the adjacent roofing elements. Adapter profiles may be fitted on the solar panel element at any edge of the solar panel element. By an adapter profile fitted to the transmission element, the profile can be fastened under, at the side and/or above the transmission element. The adapter profile may advantageously be designed in a dark material since it by placing under an overlay of a translucent transmission element will appear in the same colour range as the absorber parts under the transmission elements. The adapter profile may be of metal, plastic, composite or other weather-resistant materials, and be made of or be added a sealing profile, e.g. of EPDM, rubber or other flexible material.

In a particular embodiment of the invention, the transmission plate may be designed corrugated, e.g. as corrugated fibre-cement boards or roof tiles which are widely used roofing materials. By designing the solar panel element with a profiled surface, the solar panel element may be capable of integration into all forms of roof and facade coverings in that it is sought to follow the existing covering profiling and lines with a solar panel element which in width and/or longitudinal dimension may correspond to a multiple of existing roofing elements. There may thus be used a solar panel element which as a combined unit can be mounted in a roof surface and which appears with lines that substantially correspond to the rest of the roof surface.

In yet a particular embodiment, the transmission plate may be composed of a number of transmission elements, e.g. of the same size as diagonal slate or tile elements. By a composition of several transmission elements it is achieved that the existing covering profile and lines are followed even more longitudinally, cross-wise and obliquely. For example, an absorber housing may be covered with glass plates which are designed as diagonal slates, as the retaining flanges of the absorber housing are adapted to the fastening points common for mounting a diagonal slate roofing.

Thus it is possible to use a solar panel element which in principle takes up space corresponding to e.g. ten vertical and three horizontal rows of tiles, without the appearance of the solar panel elements deviating appreciably from the rest of the roofing.

Another possibility of establishing the lines of the roof on a solar panel element is by using loose strips which are fitted externally on the transmission plate. Such strips may be glued on the transmission plate, but may also be designed with a fastening device such that the strip can be fastened at the edges of the transmission plate. Such strips, the purpose of which is to “cheat” the eye so as to perceive a solar panel element as a part of e.g. a roof surface, can be used on plane as well as corrugated solar panel elements which are mounted in plane as well as in corrugated coverings. The said strips are typically mounted after mounting the solar panel element whereby exact positioning relative to the other lines of the roof is achieved.

By one embodiment, the solar panel element may also be designed such that individual separate transmission elements can be retrofitted immediately above a solar panel element according to the preamble of claim 1, where the absorber housing is still with a pre-fitted transmission element as well as the absorber member still can be secured at the absorber housing.

It is preferred that the absorber member is disposed at a distance from the transmission plate. This distance may e.g. be between 1 and 20 mm, but is preferred to be between 12 and 16 mm.

Hereby is achieved a certain insulating effect by the relatively still air, ensuring that no heat transmission occurs back to the surface of the transmission plate for radiation. The absorber member is most often a metal sheet which is covered by a material with high solar radiation absorption capability, a so-called technically black material which catches a predominant part of the wavelength spectrum found in sunlight. The metal sheet of the absorber member is directly connected with one or more tubes, preferably copper tubes, through which a heat absorbing medium flows and which via a piping brings the heat to a unit transforming the collected heat into heating, often heating of the hot tap water used in a household.

As mentioned above, the invention may in a particular embodiment be provided with a transmission plate designed corrugated, e.g. as corrugated fibre-cement boards or roof tiles. By also designing the absorber member and alternatively also the bottom face of the absorber housing with corresponding or substantially corresponding corrugation, an even better effect is attained as between the transmission plate and the absorber member there is thus created a constant or almost constant spacing providing a more uniform and improved heat transmission and thereby also higher efficiency in the solar panel element.

A solar panel element according to the invention may in principle be designed as a rectangular panel with a transmission plate extending beyond the absorber housing at four sides, where the transmission plate extend a suitable length in over or in under or against an edge on the surrounding roof or facade elements. Along the edge of the solar panel element there is arranged a hidden flashing for draining e.g. water. In order to achieve a roof surface which is as uniform as possible as mentioned above, the lines of the roof may be applied the solar panel element in the shape of strips which are mounted on the transmission plate. Such strips may be arranged in oblique, horizontal as well as vertical directions, respectively, and can be made of metal or other suitable material which is fixed to the outer side and/or inner side of the transmission plate.

By a flashing as mentioned above which is not visible, as the projecting means in the shape of adapter profiles extend over it, there is achieved the possibility of using solar panel elements in coverings without having a precise and completely tight joint between adapter profiles and covering.

Such a flashing in connection with a building element with projecting means along one or more edges may find application at several points in a construction. For example, it may be used in connection with solar collectors as mentioned, but also for light wells and roof windows which are not tilting windows it is suitable since the actual building element can be mounted in a hitherto unknown and integrated way. Because the building element can be mounted with an overlap in relation to the remaining covering or exactly at the same level and with a narrow gap in relation to the remaining covering, an attractive and aesthetical solution is achieved.

A further possible embodiment may be that the absorber member is disposed spaced apart from the transmission plate, and that the spacing between the absorber member and the transmission plate is constituted by at least one cavity, preferably with limited communication with the ambient atmosphere. In this context limited communication means that the cavity is closed towards the ambient atmosphere with a kind of barrier sealing the cavity. This sealing can be an airtight sealing but it does not have to be airtight thus there can be a limited mutual communication between the cavity and the ambient atmosphere.

By such a solution, the insulating effect of the cavity is enhanced appreciably, as the heat pillow formed in the cavity will not penetrate out to the ambient surroundings by convection. Furthermore, it may be advantageous to provide the closed cavity with an inert gas, like argon, since such gases have low heat transmitting ability. Alternatively, the cavity may be airless (vacuum), which also ensures a low heat transmission from the absorber member to the transmission plate.

The said solutions all reduce outward heat loss, without impairing radiation of solar heat.

In a particularly preferred embodiment, the spacing between the absorber member and the transmission plate may be constituted by a number of cavities with limited mutual communication. If the cavity between the transmission plate and the absorber member becomes too large, convection may arise in this cavity in spite of measures seeking to delimit the cavity in relation to the ambient atmosphere. This occurs as thermal actions on the solar panel element together with a natural tendency of equalising pressure differences over time will add atmospheric air to the cavity between the transmission plate and the absorber member. The continued thermal action of the solar panel element will heat this air, and by too large cavities, the heated air will rise whereby heated air will accumulate in the uppermost parts of the cavity. This means that the heat via contact with the transmission plate is transmitted to the surroundings. In order to avoid this convection problem, the cavity between the transmission plate and the absorber member may be diminished by dividing the cavity into a suitable number of smaller cavities. The division may be effected by dividing the cavity in any plane.

By a further particular embodiment, the limited mutual communication between the cavities may be constituted by one or more secondary transmission plates which preferably lie substantially in parallel with the absorber member. It is known that insulating glass units consisting of two or more parallel glass panes are provided reduced U-value if the spacing between the glasses exceeds 16 mm. This U-value reduction is caused by convection in the space between two glass panes. If a solar panel element is required to be made with a certain thickness due to external requirements, including aesthetical demands, cavities between the absorber member and the transmission plate exceeding 16 mm will have a negative influence on the efficiency of the solar panel element. This problem may be solved by inserting one or more secondary transmission elements such that heat radiation from the absorber member due to convection is reduced. For example, this may occur by disposing a double- or triple-layer insulating glass unit over the absorber member, and subsequently place the transmission element and the composite and/or corrugated transmission elements above the insulating glass unit.

In a particular variant of the invention, the limited mutual communication between the cavities may be constituted by one or more barrier members connected with the transmission plate. Hereby is achieved a sure barrier against convection as the air seeking upwards after heating will counter a limit to further rising in the form of a barrier member disposed immediately under the transmission element. The barrier member or members may e.g. be translucent materials with low transmission coefficient, such as acrylic or other types of plastic. Alternatively, the barrier member or members may appear by an integrated cantilever rib on the transmission element and under it, both in cases where the transmission element is a continuous or a composite and/or corrugated transmission element.

In another particular variant of the invention, the limited mutual communication between the cavities may be constituted by one or more barrier members connected with the absorber member. By this is achieved a less complicated technical solution to forming the said cavities as there are not necessarily any requirements to high translucency in the material used for the barrier members connected with the absorber member. To the contrary, it may be advantageous if these barrier members consist of or are applied a technically black material in order thereby to contribute to collecting the heat from the solar radiation accessing the solar panel element, such that solar radiation, besides being absorbed by the absorber member, also may be absorbed in the barrier members and via the absorber member transmitted to the heat-absorbing medium. The barrier member or members may appear by a fitted or by an integrated cantilever rib on the absorber member.

Barrier members connected with the transmission element as well as barrier members connected with the absorber member may be provided with a sealing against the absorber member and the transmission element, respectively. Thereby, further measures have been made to ensure a limited mutual connection between the cavities in order to avoid convection in the solar panel element. Moreover, it is possible that a first part of the barrier members of the solar panel element are connected with the absorber member, and where a second part of the barrier members of the solar panel element is connected with the transmission element. All of the above mentioned barrier members can be designed and composed with any thinkable geometrical patterns and shapes, whereby convection is reduced simultaneously with adding aesthetical value to the solar panel elements. Also, all of the above barrier members may be of any material which is dimensionally stable at temperatures occurring in solar panel elements. This may be plastic, metal, composite, glass or other suitable material.

In a preferred embodiment, the limited mutual communication between the cavities can be constituted by barrier members which constitute a barrier element, such as a rib element, wherein the cavities between the ribs may assume any geometric shape, e.g. rectangular, triangular, hexagonal, circular, oval or combinations of several geometrical shapes. By formation of a barrier member element, there may particularly be achieved manufacturing advantages, as the solution to the convection problems is effected by designing this barrier member element, without interfering with optimised solutions regarding the transmission element or regarding the absorber member. The barrier member element may be slats of flexible material which by combination achieve a desired rigidity for the composite material. Therefore, all prior art techniques from the carton and packing industry can be used as these techniques also concern formation of cavities by using flexible materials which by means of assembly methods attain higher strength/rigidity than the original material.

The barrier member element may e.g. be fastened to the absorber housing, the absorber member or the transmission plate, respectively, or possibly to several of these. Alternatively, the barrier member element can be disposed loosely in the solar panel element.

In a preferred embodiment of the invention, the solar panel element can be adapted to be fastened to a building part behind, e.g. a roof or façade structure, by fastening the transmission plate thereto.

Prior art fastening solutions that include a clip retainer gripping around an edge of the covering material, may be used without any problems to grip around the transmission element, as the dimensions of the transmission element correspond to the other covering material. For example, by a weather board laid slate roofing with rectangular natural slates, solar panel elements may be added as part of the roofing, where both slate tiles and solar panel elements at respective lower edges are fastened to the closest-lying lath with a clip retainer that grips around the lower edge. The upper edge of the cover elements may be secured by another clip retainer which is fastened to the closest lying lath, and where this clip retainer has resiliency, either by elastic material or by inherent spring action. The flexibility is necessary in order to maintain the possibility of adaptation by varying lath spacing.

Fastening methods for weather board roofing as described in WO 03/023164 are particularly well suited for easy mounting of rectangular slate tiles and solar panel elements according to the invention.

In a particular embodiment, the solar panel element can be adapted to be fastened to a building part behind, e.g. a roof or facade structure, by fastening the absorber housing thereto. This enables invisible fastening of the solar panel element such that solar panel elements can be built together with existing roofing types which are without visible fastening. This may e.g. be effected by fastening the solar panel element in a gripper fitting which is fastened to the underlying construction, and in which the absorber housing can be snapped on. This solution is particularly suited for incorporation into slate and tile roofs where only invisible fastening of the roof tiles is used. Slate tiles in areas without strong wind action are thus most often without the so-called storm clip retainer gripping around the lower edge of the slate tile. Roof tiles are often fastened with binders which are secured to the underlying structure and mounted in a hole or indentation at the inner side of the roof tile.

The gripper fitting may of course be further designed with a clip retainer so that the gripper fitting is securing both the lower edge of the transmission element and the absorber housing.

An embodiment to be preferred indicates that the absorber member at a side facing the building is provided with a covering of a heat insulating material. Hereby is achieved that the heat remains around the pipes to which a controlled heat absorption may occur. Moreover, it is ensured that temperatures that are damaging to the underlying materials, such as roofing underlay, wood and insulation, do not occur.

It is furthermore a possible embodiment that the transmission plate is coated, preferably at its inner side, with a material with high transmission ability for sun radiation and low transmission ability for heat radiation. The coating material is well-known in so-called low-energy insulating glass units where the material contributes to ensure minimal radiation of heat through the windows of the construction.

In a preferred variant of the invention, the said means for transforming solar radiation into heat radiation/heat conduction and for transmitting the heat radiation/heat conduction to at least one tube is constituted by a material with high absorption capability for solar radiation, e.g. a so-called technically black material which absorbs a greater part of the wavelength spectrum found in sunlight. It is advantageous to the solar panel element that the absorber member has as high absorption capability as possible for the sunlight falling on the absorber member. Thereby is transmitted as much of the energy from the sunlight as possible from the absorber member to the tubes of the solar panel element, e.g. by metallic connection between the absorber member and the tube. The energy is thereby transferred to the liquid to run through the tube or tubes disposed in the solar collector, where the tubing is provided with an inlet and a outlet connection, e.g. at the edges or underside of the solar panel element.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained below with reference to the accompanying drawing, wherein:

FIG. 1 shows a solar panel element according to the invention with a plane transmission plate;

FIG. 2 is a roof of a construction where the solar panel element forms part of the roofing.

FIG. 3 shows a solar panel element according to the invention with a profiled transmission plate.

FIG. 4 shows a solar panel element according to the invention with a composite transmission plate.

FIG. 5 a shows fastening of a solar panel element at the lower edge of the transmission plate.

FIG. 5 b shows fastening of a solar panel element at absorber holder and the lower edge of the transmission plate.

FIG. 5 c shows yet a fastening of a solar panel element.

FIG. 6 shows a cross-section of a plane solar panel element with projecting means.

FIG. 7 shows a cross-section of a corrugated solar panel element with projecting means.

FIG. 8 shows a solar panel element with adjustable strips.

FIG. 9 shows a cross-section of a solar panel element with adjustable strips.

FIG. 10 shows a cross-section of a solar panel element where transmission plate and absorber members are uniformly corrugated.

FIG. 11 shows a cross-section where the solar panel element is plane and where there is a hidden flashing.

FIG. 12 shows a second cross-section where the solar panel element is plane and where there is a hidden flashing.

FIG. 13 shows a solar panel element with flashing prior to mounting.

DETAILED DESCRIPTION OF THE INVENTION

On FIG. 1 is seen a solar panel element 1 for thermal utilisation of solar radiation 2 according to the invention. The solar panel element 1 consists of a transmission plate 3, an absorber housing 4 and an absorber member 5. The transmission plate 3 is intended for passage of radiation 2 from the sun. The absorber member 5 is provided with means 6 for transforming solar radiation 2 into heat radiation/heat conduction and with means 7 for transmitting the heat radiation/heat conduction to the two shown tubes 8. These tubes 8 are intended for passage of a heat absorbing medium 9. The absorber housing 4 is provided with means 10 for retaining the absorber member 5. The absorber housing 4 is provided with two retainer flanges 11. The transmission plate 3 provided with an inner side 12 is fastened to the two retainer flanges 11 of the absorber housing 4. The extension of the absorber housing 4 along the inner side 12 of the transmission plate 3 is less than the extension of the transmission plate 3.

FIG. 2 shows how the solar panel element 1 constitutes a covering element for roofing 13 of the roof 15 of a building construction 14. The solar panel elements 1 are here built into an existing roofing 13 without resulting in increased offset in the element overlapping 16 compared with the existing covering 17. The optical dimensions of the roof 15 are therefor largely unchanged.

From FIG. 3 appears how it is possible to design the solar panel element 1 with a profiled surface 18 which is shown here corresponding to a standard corrugated fibre-cement board. Moreover, there is shown the possibility of placing more absorber retainers 4 under a single transmission plate 3—here are thus two absorber housings 4 with room for possible existing laths between the two absorber housings 4. In order to avoid ventilating the heat over absorber members 5 away, sealing is provided between the retainer flanges 11 of the absorber housing 4 and the inner side 12 of the transmission plate 3.

On FIG. 4, the transmission plate 3 is composed of a number of transmission elements 19. Here is shown how glass sheets cut to standard measure diagonal slate may constitute such a transmission element 19. The absorber housing 4 is here equipped with retainer flanges 11 which are adapted to the fastening points common for mounting a diagonal slate roof.

FIG. 5 a shows a detailed section of a roof 15 with incorporated solar panel elements 1 a and 1 b. The solar panel element 1 a is fastened to the underlying construction 14 by a clip retainer fastening 20 of the transmission plate 3 at its lower edge 21. The clip retainer 22 is fastened to the lath 23 at a lowermost flange 24 by nailing to the lath 23. The upper edge 25 of the transmission plate 3 may be fastened in that it is pushed into the same clip retainer 22. The design of the clip retainer 22 and the size of the cantilevering 26 of the lower edge of the transmission plate beyond the retainer flange 11 of the absorber housing 4 enable that both clip retainer 22 and solar panel elements 1 can be used with other spacings between the laths 23 in a roof 15. Thereby it is possible to produce standard sizes of the solar panel elements such that these standard sizes can fit to most roof constructions.

Another fastening possibility is shown on FIG. 5 b where the solar panel element 1 is fastened to the underlying construction 14 by a clamp 27 which secures the absorber housing 4. Furthermore, the transmission plate 3 is fastened at its lower edge 21 by elongating the clamp 27 with a clip retainer part 28. Using a clamp 27 without clip retainer part 28 will enable an invisible fastening of the solar panel element 1.

A further fastening option is indicated on FIG. 5 c. The solar panel elements 1 a and 1 b are fastened to the underlying construction 14 with a longitudinal fastening 29, e.g. a bent aluminium rail which is dark on the upward facing side. The longitudinal fastening 29 is fastened to the top side of the lath 23, providing the possibility of levelling in case of minor irregularities over the extension of a lath 23. The longitudinal fastening 29 is provided with a cantilever 30 fitted in a corresponding slot 31 in the absorber housing 4 on the solar panel element 1 a. The solar panel element 1 b is secured by its upper end being placed under the longitudinal fastening 29. At the lower cantilever of the longitudinal fastening 29 there may be a sealing 32 against solar panel element 1 a and solar panel element 1 b, respectively. By a fastening solution according to FIG. 5 c there will be achieved an optically discreet fastening while at the same time, laths and other substructures are covered with dark covering, whereby the finished roof will appear uniform.

Besides the above mentioned embodiments, it is possible that the absorber housing 4 can be in direct connection with the absorber member 5, as heat transmission from the absorber part via the absorber housing 4 to the transmission element 3 is reduced by insulating packing between the absorber housing 4 and the transmission element 3. Moreover, it is possible that the retaining flanges 11 of the absorber housing 4 can be omitted in that the absorber member can be fastened indirectly to the transmission plate 3 via an intermediate transparent insulating material to which transmission plate 3 and absorber member 5 are bonded.

In order to prevent smudging and consequent requirements to periodical cleaning of the solar panel element 1, the transmission plate 3 can be applied a surface coating which by photocatalytic and/or hydrophilic and/or hydrophobic process makes the surface self-cleaning.

In FIG. 6 is seen a solar panel element 1 in cross-section where the transmission plate 3 is plane and where there are projecting means 33 along the sides. Inside the absorber housing 4 are seen a number of absorber members 5.

In FIG. 7 appears again a solar panel element 1, however this time with corrugated transmission plate 3 and also with corrugated projecting means 33. Common to the two solar panel elements in FIGS. 6 and 7 are that the projecting means 33 are in continuation of the transmission plate 3. The projecting means may be of metal, plastic, plastic, or other suitable material which is either adapted to or may be adapted to surrounding covering elements. The corrugated surface on the transmission plate 3 does not in principle need to be completely identical with the corrugation found on surrounding covering elements. Thus it is possible with a few, however well-selected standard corrugations on the transmission plate 3 in order to achieve a solar panel element 1 which can be used in connection with many different covering elements, since the differences in these are not immediately visible. It is therefore a universal design which is suited for many different corrugations.

In FIG. 8 appears a solar panel element 1 which is shown with a through-going transmission plate 3 on which is arranged four adjustable strips 34. The strips 34 are here only shown in transverse direction, but may also be mounted in the longitudinal direction or obliquely. There may be strips 34 in several directions on a transmission element 3 without problems. The strips 34 may be bonded to the transmission plate 3, or they may be fixed in other ways. After mounting the solar panel element 1, the said strips 34 may be mounted or adjusted such that they are flush with the surrounding covering elements, whereby the solar panel element 1 will not differ so markedly from the surface in which it is mounted.

In FIG. 9 is seen a solar panel element 1 in cross-section where the transmission plate 3 is mounted on an absorber housing 4, in which a number of absorber members 5 are fitted. Externally of the transmission plate 3 is mounted a strip 34 which at its ends is provided with a hook member 35 whereby the strip 34 is fixed to the transmission plate 3. The strip 34 may e.g. be made of steel and may thus in principle be clicked on the transmission plate 3 like a kind of spring.

In FIG. 10 appears a variant of a solar panel element 1 where the transmission plate 3 is corrugated and where the absorber members 5 are designed with a substantially corresponding corrugation such that the distance between the transmission plate 3 and the absorber members 5 are about the same.

In FIG. 11 appears a cross-section of a solar panel element 1 with a transmission plate 3 and an absorber housing 4 with a number of absorber members 5. The transmission plate 3 in the shown embodiment is mounted at the same level as the surrounding covering elements 36. Along the sides of the absorber housing 4, a flashing 37 is fitted which is not visible from the roof surface but which is necessary due to the narrow gap 38 between the transmission plate 3 and the surrounding covering elements 36.

In FIG. 12, the same solar panel element 1 as in FIG. 11 appears in cross-section, but viewed from the side and shown with a typical inclination corresponding to the slope of a not shown roof construction. At the upper edge of the absorber housing 4 appears a flashing 37 which substantially corresponds that shown in FIG. 11 and which here appears as a thick line along the bottom of the absorber housing 4. At the bottom of the solar panel element 1 is seen that the flashing 37 is designed with a bend 39 such that water can be conducted from the flashing 37 and out on the external roof surface.

In FIG. 13 is seen the same solar panel element 1 as shown in FIGS. 11 and 12, but here shown isometrically with flashing 37, 39 and with strips 34. 

1-11. (canceled)
 12. A solar panel element for installation in relation to a surrounding covering, for thermal utilisation of solar radiation, the solar panel element constituting a roof or facade element for covering a building, the solar panel element including a transmission sheet or plate, an absorber member and an absorber housing, where the transmission plate is adapted for passage of solar radiation, where the absorber member includes means for transforming solar radiation to heat radiation/heat conduction and for transmitting the heat radiation/heat conduction to at least one tube which is connected with the absorber member, and which is intended for containing a heat absorbing liquid medium, where the absorber housing includes connecting means for the transmission sheet or plate, where the solar panel element is provided with projecting means along one or more edges, where these means form direct or indirect transition to the surrounding covering and at the same time are an extension of the transmission plate, said surrounding covering forming lines in a longitudinally, crosswise and/or obliquely direction, said lines being foamed by the profile and/or edge of individual covering elements, wherein the transmission plate or plates are provided with arrange able means for indicating lines having a longitudinally, crosswise and/or obliquely direction.
 13. Solar panel element according to claim 12, wherein the transmission plate is composed of a number of transmission elements, e.g. of the same size as diagonal slate or tile elements.
 14. Solar panel element according to claim 12, wherein the solar panel element is designed corrugated, e.g. as corrugated fibre-cement board or roof tiles, and that the projecting means are adapted to, or designed to be adapted to, surrounding covering elements.
 15. Solar panel element according to claim 12, wherein the solar panel element at least at one side and preferably at several sides includes a flashing, where the flashing as well as the solar panel element is designed such that the flashing is hidden by the surrounding covering elements, alternatively by the projecting means.
 16. Solar panel element according to claim 12, wherein the absorber member is spaced apart from the transmission plate, and that the spacing between the absorber member and the transmission plate is constituted by at least one cavity, wherein the at least one cavity preferably contains a gas which is heavier than atmospheric air or provided with a pressure which is less that atmospheric pressure.
 17. Solar panel element according to claim 12, wherein the spacing between the absorber member and the transmission plate is constituted by a number of cavities with limited mutual communication.
 18. Solar panel element according to claim 17, wherein the limited mutual communication between the cavities is constituted by one or more secondary transmission plates which preferably lie substantially in parallel with the absorber member.
 19. Solar panel element according to claim 17, wherein the limited mutual communication between the cavities is constituted by one or more barrier members connected with the transmission plate or with the absorber member.
 20. Solar panel element according to claim 16, wherein the limited mutual communication between the cavities is constituted by barrier members which constitute a barrier element, such as a rib element, wherein the cavities between the ribs may assume any geometric shape, e.g. rectangular, triangular, hexagonal, circular, oval or combinations of several geometrical shapes.
 21. Solar panel element according to claim 12, wherein the transmission plate as well as the absorber member, and alternatively also the bottom surface of the absorber housing, are provided with corresponding or substantially uniform corrugations. 